@inbook{1210, abstract = {Mechanisms for cell protection are essential for survival of multicellular organisms. In plants, the apical hook, which is transiently formed in darkness when the germinating seedling penetrates towards the soil surface, plays such protective role and shields the vitally important shoot apical meristem and cotyledons from damage. The apical hook is formed by bending of the upper hypocotyl soon after germination, and it is maintained in a closed stage while the hypocotyl continues to penetrate through the soil and rapidly opens when exposed to light in proximity of the soil surface. To uncover the complex molecular network orchestrating this spatiotemporally tightly coordinated process, monitoring of the apical hook development in real time is indispensable. Here we describe an imaging platform that enables high-resolution kinetic analysis of this dynamic developmental process. © Springer Science+Business Media New York 2017.}, author = {Zhu, Qiang and Žádníková, Petra and Smet, Dajo and Van Der Straeten, Dominique and Benková, Eva}, booktitle = {Plant Hormones}, pages = {1 -- 8}, publisher = {Humana Press}, title = {{Real time analysis of the apical hook development}}, doi = {10.1007/978-1-4939-6469-7_1}, volume = {1497}, year = {2016}, } @article{1212, abstract = {Plants adjust their growth according to gravity. Gravitropism involves gravity perception, signal transduction, and asymmetric growth response, with organ bending as a consequence [1]. Asymmetric growth results from the asymmetric distribution of the plant-specific signaling molecule auxin [2] that is generated by lateral transport, mediated in the hypocotyl predominantly by the auxin transporter PIN-FORMED3 (PIN3) [3–5]. Gravity stimulation polarizes PIN3 to the bottom sides of endodermal cells, correlating with increased auxin accumulation in adjacent tissues at the lower side of the stimulated organ, where auxin induces cell elongation and, hence, organ bending. A curvature response allows the hypocotyl to resume straight growth at a defined angle [6], implying that at some point auxin symmetry is restored to prevent overbending. Here, we present initial insights into cellular and molecular mechanisms that lead to the termination of the tropic response. We identified an auxin feedback on PIN3 polarization as underlying mechanism that restores symmetry of the PIN3-dependent auxin flow. Thus, two mechanistically distinct PIN3 polarization events redirect auxin fluxes at different time points of the gravity response: first, gravity-mediated redirection of PIN3-mediated auxin flow toward the lower hypocotyl side, where auxin gradually accumulates and promotes growth, and later PIN3 polarization to the opposite cell side, depleting this auxin maximum to end the bending. Accordingly, genetic or pharmacological interference with the late PIN3 polarization prevents termination of the response and leads to hypocotyl overbending. This observation reveals a role of auxin feedback on PIN polarity in the termination of the tropic response. © 2016 Elsevier Ltd}, author = {Rakusová, Hana and Abbas, Mohamad and Han, Huibin and Song, Siyuan and Robert, Hélène and Friml, Jirí}, journal = {Current Biology}, number = {22}, pages = {3026 -- 3032}, publisher = {Cell Press}, title = {{Termination of shoot gravitropic responses by auxin feedback on PIN3 polarity}}, doi = {10.1016/j.cub.2016.08.067}, volume = {26}, year = {2016}, } @inproceedings{1214, abstract = {With the accelerated development of robot technologies, optimal control becomes one of the central themes of research. In traditional approaches, the controller, by its internal functionality, finds appropriate actions on the basis of the history of sensor values, guided by the goals, intentions, objectives, learning schemes, and so forth. While very successful with classical robots, these methods run into severe difficulties when applied to soft robots, a new field of robotics with large interest for human-robot interaction. We claim that a novel controller paradigm opens new perspective for this field. This paper applies a recently developed neuro controller with differential extrinsic synaptic plasticity to a muscle-tendon driven arm-shoulder system from the Myorobotics toolkit. In the experiments, we observe a vast variety of self-organized behavior patterns: when left alone, the arm realizes pseudo-random sequences of different poses. By applying physical forces, the system can be entrained into definite motion patterns like wiping a table. Most interestingly, after attaching an object, the controller gets in a functional resonance with the object's internal dynamics, starting to shake spontaneously bottles half-filled with water or sensitively driving an attached pendulum into a circular mode. When attached to the crank of a wheel the neural system independently develops to rotate it. In this way, the robot discovers affordances of objects its body is interacting with.}, author = {Martius, Georg S and Hostettler, Raphael and Knoll, Alois and Der, Ralf}, location = {Daejeon, Korea}, publisher = {IEEE}, title = {{Compliant control for soft robots: Emergent behavior of a tendon driven anthropomorphic arm}}, doi = {10.1109/IROS.2016.7759138}, volume = {2016-November}, year = {2016}, } @article{261, abstract = {Let G = SL(2, R) ⋉R2 and Γ = SL(2, Z) ⋉Z2. Building on recent work of Strömbergsson, we prove a rate of equidistribution for the orbits of a certain one-dimensional unipotent flow of Γ\G, which projects to a closed horocycle in the unit tangent bundle to the modular surface. We use this to answer a question of Elkies and McMullen by making effective the convergence of the gap distribution of √n mod 1.}, author = {Timothy Browning and Vinogradov, Ilya}, journal = {Journal of the London Mathematical Society}, number = {1}, pages = {61 -- 84}, publisher = {John Wiley and Sons Ltd}, title = {{Effective ratner theorem for SL (2, R) ⋉R2 and gaps in √n modulo 1}}, doi = {10.1112/jlms/jdw025}, volume = {94}, year = {2016}, } @article{262, abstract = {For any number field we calculate the exact proportion of rational numbers which are everywhere locally a norm but not globally a norm from the number field.}, author = {Timothy Browning and Newton, Rachel}, journal = {Mathematika}, number = {2}, pages = {337 -- 347}, publisher = {Cambridge University Press}, title = {{The proportion of failures of the Hasse norm principle}}, doi = {10.1112/S0025579315000261}, volume = {62}, year = {2016}, } @article{263, abstract = {We count rational points of bounded height on the Cayley ruled cubic surface and interpret the result in the context of general conjectures due to Batyrev and Tschinkel.}, author = {de la Bretèche, Régis and Timothy Browning and Salberger, Per}, journal = {European Journal of Mathematics}, number = {1}, pages = {55 -- 72}, publisher = {Springer Nature}, title = {{Counting rational points on the Cayley ruled cubic}}, doi = {10.1007/s40879-015-0049-1}, volume = {2}, year = {2016}, } @article{264, abstract = {Given a family of varieties over a number field, we determine conditions under which there is a Brauer-Manin obstruction to weak approximation for 100% of the fibres which are everywhere locally soluble.}, author = {Bright, Maritn J and Timothy Browning and Loughran, Daniel}, journal = {Compositio Mathematica}, number = {7}, pages = {1435 -- 1475}, publisher = {Cambridge University Press}, title = {{Failures of weak approximation in families}}, doi = {10.1112/S0010437X16007405}, volume = {152}, year = {2016}, } @article{363, abstract = {Lead halide perovskite materials have attracted significant attention in the context of photovoltaics and other optoelectronic applications, and recently, research efforts have been directed to nanostructured lead halide perovskites. Collodial nanocrystals (NCs) of cesium lead halides (CsPbX3, X = Cl, Br, I) exhibit bright photoluminescence, with emission tunable over the entire visible spectral region. However, previous studies on CsPbX3 NCs did not address key aspects of their chemistry and photophysics such as surface chemistry and quantitative light absorption. Here, we elaborate on the synthesis of CsPbBr3 NCs and their surface chemistry. In addition, the intrinsic absorption coefficient was determined experimentally by combining elemental analysis with accurate optical absorption measurements. 1H solution nuclear magnetic resonance spectroscopy was used to characterize sample purity, elucidate the surface chemistry, and evaluate the influence of purification methods on the surface composition. We find that ligand binding to the NC surface is highly dynamic, and therefore, ligands are easily lost during the isolation and purification procedures. However, when a small amount of both oleic acid and oleylamine is added, the NCs can be purified, maintaining optical, colloidal, and material integrity. In addition, we find that a high amine content in the ligand shell increases the quantum yield due to the improved binding of the carboxylic acid.}, author = {De Roo, Jonathan and Ibáñez, Maria and Geiregat, Pieter and Nedelcu, Georgian and Walravens, Willem and Maes, Jorick and Martins, Jose and Van Driessche, Isabel and Kovalenko, Maksym and Hens, Zeger}, journal = {ACS Nano}, number = {2}, pages = {2071 -- 2081}, publisher = {American Chemical Society}, title = {{Highly dynamic ligand binding and light absorption coefficient of cesium lead bromide perovskite nanocrystals}}, doi = {10.1021/acsnano.5b06295}, volume = {10}, year = {2016}, } @article{364, abstract = {The development of highly active, low cost and stable electrocatalysts for direct alcohol fuel cells remains a critical challenge. While Pd2Sn has been reported as an excellent catalyst for the ethanol oxidation reaction (EOR), here we present DFT analysis results showing the (100) and (001) facets of orthorhombic Pd2Sn to be more favourable for the EOR than (010). Accordingly, using tri-n-octylphosphine, oleylamine (OLA) and methylamine hydrochloride as size and shape directing agents, we produced colloidal Pd2Sn nanorods (NRs) grown in the [010] direction. Such Pd2Sn NRs, supported on graphitic carbon, showed excellent performance and stability as an anode electrocatalyst for the EOR in alkaline media, exhibiting 3 times and 10 times higher EOR current densities than that of Pd2Sn and Pd nanospheres, respectively. We associate this improved performance with the favourable faceting of the NRs.}, author = {Luo, Zhishan and Lu, Jianmin and Flox, Cristina and Nafria, Raquel and Genç, Aziz and Arbiol, Jordi and Llorca, Jordi and Ibanez Sabate, Maria and Morante, Joan and Cabot, Andreu}, journal = {Journal of Materials Chemistry A}, number = {42}, pages = {16706 -- 16713}, publisher = {Royal Society of Chemistry}, title = {{Pd2Sn [010] nanorods as a highly active and stable ethanol oxidation catalyst}}, doi = {10.1039/c6ta06430b}, volume = {4}, year = {2016}, } @article{366, abstract = {Cesium lead halide (CsPbX3, X = Cl, Br, I) nanocrystals (NCs) offer exceptional optical properties for several potential applications but their implementation is hindered by a low chemical and structural stability and limited processability. In the present work, we developed a new method to efficiently coat CsPbX3 NCs, which resulted in their increased chemical and optical stability as well as processability. The method is based on the incorporation of poly(maleic anhydride-alt-1-octadecene) (PMA) into the synthesis of the perovskite NCs. The presence of PMA in the ligand shell stabilizes the NCs by tightening the ligand binding, limiting in this way the NC surface interaction with the surrounding media. We further show that these NCs can be embedded in self-standing silicone/glass plates as down-conversion filters for the fabrication of monochromatic green and white light emitting diodes (LEDs) with narrow bandwidths and appealing color characteristics.}, author = {Meyn, Michaela and Perálvarez, Mariano and Heuer Jungemann, Amelie and Hertog, Wim and Ibanez Sabate, Maria and Nafria, Raquel and Genç, Aziz and Arbiol, Jordi and Kovalenko, Maksym and Carreras, Josep and Cabot, Andreu and Kanaras, Antonios}, journal = {ACS Applied Materials and Interfaces}, number = {30}, pages = {19579 -- 19586}, publisher = {American Chemical Society}, title = {{Polymer enhanced stability of inorganic perovskite nanocrystals and their application in color conversion LEDs}}, doi = {10.1021/acsami.6b02529}, volume = {8}, year = {2016}, } @article{367, abstract = {The functional properties of quaternary I2–II–IV–VI4 nanomaterials, with potential interest in various technological fields, are highly sensitive to compositional variations, which is a challenging parameter to adjust. Here we demonstrate the presence of phosphonic acids to aid controlling the reactivity of the II element monomer to be incorporated in quaternary Cu2ZnSnSe4 nanoparticles and thus to provide a more reliable way to adjust the final nanoparticle metal ratios. Furthermore, we demonstrate the composition control in such multivalence nanoparticles to allow modifying charge carrier concentrations in nanomaterials produced from the assembly of these building blocks. }, author = {Ibáñez, Maria and Berestok, Taisiia and Dobrozhan, Oleksandr and Lalonde, Aaron and Izquierdo Roca, Victor and Shavel, Alexey and Pérez Rodríguez, Alejandro and Snyder, G Jeffrey and Cabot, Andreu}, journal = {Journal of Nanoparticle Research}, number = {8}, publisher = {Springer}, title = {{Phosphonic acids aid composition adjustment in the synthesis of Cu2+xZn1−xSnSe4−y nanoparticles}}, doi = {10.1007/s11051-016-3545-4}, volume = {18}, year = {2016}, } @article{368, abstract = {The control of the phase distribution in multicomponent nanomaterials is critical to optimize their catalytic performance. In this direction, while impressive advances have been achieved in the past decade in the synthesis of multicomponent nanoparticles and nanocomposites, element rearrangement during catalyst activation has been frequently overseen. Here, we present a facile galvanic replacement-based procedure to synthesize Co@Cu nanoparticles with narrow size and composition distributions. We further characterize their phase arrangement before and after catalytic activation. When oxidized at 350 °C in air to remove organics, Co@Cu core-shell nanostructures oxidize to polycrystalline CuO-Co3O4 nanoparticles with randomly distributed CuO and Co3O4 crystallites. During a posterior reduction treatment in H2 atmosphere, Cu precipitates in a metallic core and Co migrates to the nanoparticle surface to form Cu@Co core-shell nanostructures. The catalytic behavior of such Cu@Co nanoparticles supported on mesoporous silica was further analyzed toward CO2 hydrogenation in real working conditions.}, author = {Nafria, Raquel and Genç, Aziz and Ibáñez, Maria and Arbiol, Jprdi and Ramírez De La Piscina, Pilar and Homs, Narcís and Cabot, Andreu}, journal = {Langmuir}, number = {9}, pages = {2267 -- 2276}, publisher = {American Chemical Society}, title = {{Co Cu nanoparticles synthesis by galvanic replacement and phase rearrangement during catalytic activation}}, doi = {10.1021/acs.langmuir.5b04622}, volume = {32}, year = {2016}, } @article{369, abstract = {The efficient conversion between thermal and electrical energy by means of durable, silent and scalable solid-state thermoelectric devices has been a long standing goal. While nanocrystalline materials have already led to substantially higher thermoelectric efficiencies, further improvements are expected to arise from precise chemical engineering of nanoscale building blocks and interfaces. Here we present a simple and versatile bottom-up strategy based on the assembly of colloidal nanocrystals to produce consolidated yet nanostructured thermoelectric materials. In the case study on the PbS-Ag system, Ag nanodomains not only contribute to block phonon propagation, but also provide electrons to the PbS host semiconductor and reduce the PbS intergrain energy barriers for charge transport. Thus, PbS-Ag nanocomposites exhibit reduced thermal conductivities and higher charge carrier concentrations and mobilities than PbS nanomaterial. Such improvements of the material transport properties provide thermoelectric figures of merit up to 1.7 at 850 K.}, author = {Ibanez Sabate, Maria and Luo, Zhishan and Genç, Azoz and Piveteau, Laura and Ortega, Silvia and Cadavid, Doris and Dobrozhan, Oleksandr and Liu, Yu and Nachtegaal, Maarten and Zebarjadi, Mona and Arbiol, Jordi and Kovalenko, Maksym and Cabot, Andreu}, journal = {Nature Communications}, publisher = {Nature Publishing Group}, title = {{High performance thermoelectric nanocomposites from nanocrystal building blocks}}, doi = {doi:10.1038/ncomms10766}, volume = {7}, year = {2016}, } @article{370, abstract = {Copper-based chalcogenides that comprise abundant, low-cost, and environmental friendly elements are excellent materials for a number of energy conversion applications, including photovoltaics, photocatalysis, and thermoelectrics (TE). In such applications, the use of solution-processed nanocrystals (NCs) to produce thin films or bulk nanomaterials has associated several potential advantages, such as high material yield and throughput, and composition control with unmatched spatial resolution and cost. Here we report on the production of Cu3SbSe4 (CASe) NCs with tuned amounts of Sn and Bi dopants. After proper ligand removal, as monitored by nuclear magnetic resonance and infrared spectroscopy, these NCs were used to produce dense CASe bulk nanomaterials for solid state TE energy conversion. By adjusting the amount of extrinsic dopants, dimensionless TE figures of merit (ZT) up to 1.26 at 673 K were reached. Such high ZT values are related to an optimized carrier concentration by Sn doping, a minimized lattice thermal conductivity due to efficient phonon scattering at point defects and grain boundaries, and to an increase of the Seebeck coefficient obtained by a modification of the electronic band structure with Bi doping. Nanomaterials were further employed to fabricate ring-shaped TE generators to be coupled to hot pipes, which provided 20 mV and 1 mW per TE element when exposed to a 160 °C temperature gradient. The simple design and good thermal contact associated with the ring geometry and the potential low cost of the material solution processing may allow the fabrication of TE generators with short payback times.}, author = {Liu, Yu and García, Gregorio and Ortega, Silvia and Cadavid, Doris and Palacios, Pablo and Lu, Jinyu and Ibanez, Maria and Xi, Lili and De Roo, Jonathan and López, Antonio and Márti Sánchez, Sara and Cabezas, Ignasi and De La Mata, Maria and Luo, Zhishan and Dun, Chaocha and Dobrozhan, Oleksandr and Carroll, David and Zhang, Wenging and Martins, José and Kovalenko, Mksym and Arbiol, Jordi and Noriega, German and Song, Jiming and Wahnón, Perla and Cabot, Andreu}, journal = {Journal of Materials Chemistry A}, number = {6}, pages = {2592 -- 2602}, publisher = {Royal Society of Chemistry}, title = {{Solution based synthesis and processing of Sn and Bi doped Cu inf 3 inf SbSe inf 4 inf nanocrystals nanomaterials and ring shaped thermoelectric generators}}, doi = {10.1039/C6TA08467B}, volume = {5}, year = {2016}, } @article{371, abstract = {The design and engineering of earth-abundant catalysts that are both cost-effective and highly active for water splitting are crucial challenges in a number of energy conversion and storage technologies. In this direction, herein we report the synthesis of Fe3O4@NiFexOy core-shell nanoheterostructures and the characterization of their electrocatalytic performance toward the oxygen evolution reaction (OER). Such nanoparticles (NPs) were produced by a two-step synthesis procedure involving the colloidal synthesis of Fe3O4 nanocubes with a defective shell and the posterior diffusion of nickel cations within this defective shell. Fe3O4@NiFexOy NPs were subsequently spin-coated over ITO-covered glass and their electrocatalytic activity toward water oxidation in carbonate electrolyte was characterized. Fe3O4@NiFexOy catalysts reached current densities above 1 mA/cm2 with a 410 mV overpotential and Tafel slopes of 48 mV/dec, which is among the best electrocatalytic performances reported in carbonate electrolyte.}, author = {Luo, Zhishan and Márti Sánchez, Sara and Nafria, Raquel and Joshua, Gihan and De La Mata, Maria and Guardia, Pablo and Flox, Christina and Martínez Boubeta, Carlos and Simeonidis, Konstantinos and Llorca, Jordi and Morante, Joan and Arbiol, Jordi and Ibanez Sabate, Maria and Cabot, Andreu}, journal = {ACS Applied Materials and Interfaces}, number = {43}, pages = {29461 -- 29469}, publisher = {American Chemical Society}, title = {{Fe3O4@NiFexOy nanoparticles with enhanced electrocatalytic properties for oxygen evolution in carbonate electrolyte}}, doi = {10.1021/acsami.6b09888}, volume = {8}, year = {2016}, } @article{372, abstract = {The optimization of a material functionality requires both the rational design and precise engineering of its structural and chemical parameters. In this work, we show how colloidal chemistry is an excellent synthetic choice for the synthesis of novel ternary nanostructured chalcogenides, containing exclusively noble metals, with tailored morphology and composition and with potential application in the energy conversion field. Specifically, the Ag-Au-Se system has been explored from a synthetic point of view, which leads to a set of Ag2Se-based hybrid and ternary nanoparticles including the room temperature synthesis of the rare ternary Ag3AuSe2 fischesserite phase. An in-depth structural and chemical characterization of all nanomaterials has been performed, which proofed especially useful for unravelling the reaction mechanism behind the formation of the ternary phase in solution. The work is complemented with the thermal and electric characterization of a ternary Ag-Au-Se nanocomposite with promising results: we found that the use of the ternary nanocomposite represents a clear improvement in terms of thermoelectric energy conversion as compared to a binary Ag-Se nanocomposite analogue. }, author = {Dalmases, Mariona and Ibanez Sabate, Maria and Torruella, Paul and Fernàndez Altable, Victor and López Conesa, Luis and Cadavid, Doris and Piveteau, Laura and Nachtegaal, Maarten and Llorca, Jordi and Ruiz González, Maria and Estradé, Sònia and Peiró, Francesca and Kovalenko, Maksym and Cabot, Andreu and Figuerola, Albert}, journal = {Chemistry of Materials}, number = {19}, pages = {7017 -- 7028}, publisher = {American Chemical Society}, title = {{Synthesis and thermoelectric properties of noble metal ternary chalcogenide systems of Ag Au Se in the forms of alloyed nanoparticles and colloidal nanoheterostructures}}, doi = {10.1021/acs.chemmater.6b02845}, volume = {28}, year = {2016}, } @article{379, abstract = {Monodisperse Cu2ZnSnS4 (CZTS) nanocrystals (NCs), with quasi-spherical shape, were prepared by a facile, high-yield, scalable, and high-concentration heat-up procedure. The key parameters to minimize the NC size distribution were efficient mixing and heat transfer in the reaction mixture through intensive argon bubbling and improved control of the heating ramp stability. Optimized synthetic conditions allowed the production of several grams of highly monodisperse CZTS NCs per batch, with up to 5 wt % concentration in a crude solution and a yield above 90%.}, author = {Shavel, Alexey and Ibáñez, Maria and Luo, Zhishan and De Roo, Jonathan and Carrete, Alex and Dimitrievska, Mirjana and Genç, Aziz and Meyns, Michaela and Pérez Rodríguez, Alejandro and Kovalenko, Maksym and Arbol, Jordi and Cabot, Andreu}, journal = {Chemistry of Materials}, number = {3}, pages = {720 -- 726}, publisher = {American Chemical Society}, title = {{Scalable heating-up synthesis of monodisperse Cu2ZnSnS4 nanocrystals}}, doi = {10.1021/acs.chemmater.5b03417}, volume = {28}, year = {2016}, } @article{380, abstract = {Size and shape tunability and low-cost solution processability make colloidal lead chalcogenide quantum dots (QDs) an emerging class of building blocks for innovative photovoltaic, thermoelectric and optoelectronic devices. Lead chalcogenide QDs are known to crystallize in the rock-salt structure, although with very different atomic order and stoichiometry in the core and surface regions; however, there exists no convincing prior identification of how extreme downsizing and surface-induced ligand effects influence structural distortion. Using forefront X-ray scattering techniques and density functional theory calculations, here we have identified that, at sizes below 8 nm, PbS and PbSe QDs undergo a lattice distortion with displacement of the Pb sublattice, driven by ligand-induced tensile strain. The resulting permanent electric dipoles may have implications on the oriented attachment of these QDs. Evidence is found for a Pb-deficient core and, in the as-synthesized QDs, for a rhombic dodecahedral shape with nonpolar {110} facets. On varying the nature of the surface ligands, differences in lattice strains are found.}, author = {Bertolotti, Federica and Dirin, Dmitry and Ibanez Sabate, Maria and Krumreich, Frank and Cervellino, Antonio and Frison, Ruggero and Voznyy, Oleksandr and Sargent, Edward and Kovalenko, Maksym and Guagliardi, Antonietta and Masciocchi, Norberto}, journal = {Nature Materials}, pages = {987 -- 994}, publisher = {Nature Publishing Group}, title = {{Crystal symmetry breaking and role of vacancies in colloidal lead chalcogenide quantum dots}}, doi = {10.1038/NMAT4661}, volume = {15}, year = {2016}, } @article{381, abstract = {We present a high-yield and scalable colloidal synthesis to produce monodisperse AgSbSe2 nanocrystals (NCs). Using nuclear magnetic resonance (NMR) spectroscopy, we characterized the NC surface chemistry and demonstrate the presence of surfactants in dynamic exchange, which controls the NC growth mechanism. In addition, these NCs were electronically doped by introducing small amounts of bismuth. To demonstrate the technological potential of such processed material, after ligand removal by means of NaNH2, AgSbSe2 NCs were used as building blocks to produce thermoelectric (TE) nanomaterials. A preliminary optimization of the doping concentration resulted in a thermoelectric figure of merit (ZT) of 1.1 at 640 K, which is comparable to the best ZT values obtained with a Pb- and Te-free material in this middle temperature range, with the additional advantage of the high versatility and low cost associated with solution processing technologies.}, author = {Liu, Yu and Cadavid, Doris and Ibanez Sabate, Maria and De Roo, Jonathan and Ortega, Silvia and Dobrozhan, Oleksandr and Kovalenko, Maksym and Cabot, Andreu}, journal = {Journal of Materials Chemistry C}, pages = {4756 -- 4762}, publisher = {Royal Society of Chemistry}, title = {{Colloidal AgSbSe2 nanocrystals: surface analysis, electronic doping and processing into thermoelectric nanomaterials}}, doi = {10.1039/c6tc00893c}, volume = {4}, year = {2016}, } @article{382, abstract = {Mn3O4@CoMn2O4 nanoparticles (NPs) were produced at low temperature and ambient atmosphere using a one-pot two-step synthesis protocol involving the cation exchange of Mn by Co in preformed Mn3O4 NPs. Selecting the proper cobalt precursor, the nucleation of CoxOy crystallites at the Mn3O4@CoMn2O4 surface could be simultaneously promoted to form Mn3O4@CoMn2O4–CoxOy NPs. Such heterostructured NPs were investigated for oxygen reduction and evolution reactions (ORR, OER) in alkaline solution. Mn3O4@CoMn2O4–CoxOy NPs with [Co]/[Mn] = 1 showed low overpotentials of 0.31 V at −3 mA·cm–2 and a small Tafel slope of 52 mV·dec–1 for ORR, and overpotentials of 0.31 V at 10 mA·cm–2 and a Tafel slope of 81 mV·dec–1 for OER, thus outperforming commercial Pt-, IrO2-based and previously reported transition metal oxides. This cation-exchange-based synthesis protocol opens up a new approach to design novel heterostructured NPs as efficient nonprecious metal bifunctional oxygen catalysts.}, author = {Luo, Zhishan and Irtem, Erdem and Ibanez, Maria and Nafria, Raquel and Márti Sánchez, Sara and Genç, Aziz and De La Mata, Maria and Liu, Yu and Cadavid, Doris and Llorca, Jordi and Arbiol, Jordi and Andreu, Teresa and Morante, Joan and Cabot, Andreu}, journal = {ACS Applied Materials and Interfaces}, pages = {17435 -- 17444}, publisher = {American Chemical Society}, title = {{Mn3O4@CoMn2O4–CoxOy nanoparticles: Partial cation exchange synthesis and electrocatalytic properties toward the oxygen reduction and evolution reactions}}, doi = {10.1021/acsami.6b02786}, volume = {8}, year = {2016}, }